Aster glehni Ethanol Extract Inhibits Inflammatory Responses Regulating Skin Barrier Molecules in Human Keratinocytes

Prolonged skin inflammation is caused by disrupted skin barrier resulting in chronic inflammatory diseases such as atopic dermatitis. As a potent natural product with anti-inflammatory property, Aster glehni (A. glehni) is a traditional edible herb and has been used to treat diabetes or colitis-associated colon cancer. In present study, we figured out an additional effect of A. glehni ethanol extract (AGE) in pro-inflammatory cytokines-stimulated human keratinocytes. Mixture of tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) was used to induce inflammatory responses in the HaCaT keratinocytes. AGE suppressed activation of ERK mitogen-activated protein kinase, nuclear factor (NF)-κB, and signal transducer and activator of transcription 1 and 3 (STAT1 and STAT3). The treatment of AGE inhibited mRNA expressions of pro-inflammatory cytokines in TNF-α and IFN-γ-stimulated HaCaT cells. Also, AGE induced up-regulated expressions of skin barrier molecules like filaggrin, loricrin, or ZO-1. We evaluated the effects of AGE on protein or mRNA expression levels using western blot or qRT-PCR, respectively. Taken together, these results suggest that the treatment of AGE exerts anti-inflammatory effect on keratinocytes through suppressing inflammatory signaling pathways and up-regulating skin molecules in HaCaT keratinocytes.